usb: xhci: add debugfs support for ep with stream

To show the trb ring of streams, use the exsiting ring files of bulk ep
to show trb ring of one specific stream ID, which stream ID's trb ring
will be shown, is controlled by a new debugfs file stream_id, this is to
avoid to create a large number of dir for every allocate stream IDs,
another debugfs file stream_context_array is created to show all the
allocated stream context array entries.

Signed-off-by: Li Jun <[e-mail]>
Signed-off-by: Mathias Nyman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/xhci-debugfs.c

···
 	if (!epriv)
 		return;
 
+	epriv->show_ring = dev->eps[ep_index].ring;
+
 	snprintf(epriv->name, sizeof(epriv->name), "ep%02d", ep_index);
 	epriv->root = xhci_debugfs_create_ring_dir(xhci,
-						   &dev->eps[ep_index].ring,
+						   &epriv->show_ring,
 						   epriv->name,
 						   spriv->root);
 	spriv->eps[ep_index] = epriv;
···
 	debugfs_remove_recursive(epriv->root);
 	spriv->eps[ep_index] = NULL;
 	kfree(epriv);
+}
+
+static int xhci_stream_id_show(struct seq_file *s, void *unused)
+{
+	struct xhci_ep_priv	*epriv = s->private;
+
+	if (!epriv->stream_info)
+		return -EPERM;
+
+	seq_printf(s, "Show stream ID %d trb ring, supported [1 - %d]\n",
+		   epriv->stream_id, epriv->stream_info->num_streams - 1);
+
+	return 0;
+}
+
+static int xhci_stream_id_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, xhci_stream_id_show, inode->i_private);
+}
+
+static ssize_t xhci_stream_id_write(struct file *file,  const char __user *ubuf,
+			       size_t count, loff_t *ppos)
+{
+	struct seq_file         *s = file->private_data;
+	struct xhci_ep_priv	*epriv = s->private;
+	int			ret;
+	u16			stream_id; /* MaxPStreams + 1 <= 16 */
+
+	if (!epriv->stream_info)
+		return -EPERM;
+
+	/* Decimal number */
+	ret = kstrtou16_from_user(ubuf, count, 10, &stream_id);
+	if (ret)
+		return ret;
+
+	if (stream_id == 0 || stream_id >= epriv->stream_info->num_streams)
+		return -EINVAL;
+
+	epriv->stream_id = stream_id;
+	epriv->show_ring = epriv->stream_info->stream_rings[stream_id];
+
+	return count;
+}
+
+static const struct file_operations stream_id_fops = {
+	.open			= xhci_stream_id_open,
+	.write                  = xhci_stream_id_write,
+	.read			= seq_read,
+	.llseek			= seq_lseek,
+	.release		= single_release,
+};
+
+static int xhci_stream_context_array_show(struct seq_file *s, void *unused)
+{
+	struct xhci_ep_priv	*epriv = s->private;
+	struct xhci_stream_ctx	*stream_ctx;
+	dma_addr_t		dma;
+	int			id;
+
+	if (!epriv->stream_info)
+		return -EPERM;
+
+	seq_printf(s, "Allocated %d streams and %d stream context array entries\n",
+			epriv->stream_info->num_streams,
+			epriv->stream_info->num_stream_ctxs);
+
+	for (id = 0; id < epriv->stream_info->num_stream_ctxs; id++) {
+		stream_ctx = epriv->stream_info->stream_ctx_array + id;
+		dma = epriv->stream_info->ctx_array_dma + id * 16;
+		if (id < epriv->stream_info->num_streams)
+			seq_printf(s, "%pad stream id %d deq %016llx\n", &dma,
+				   id, le64_to_cpu(stream_ctx->stream_ring));
+		else
+			seq_printf(s, "%pad stream context entry not used deq %016llx\n",
+				   &dma, le64_to_cpu(stream_ctx->stream_ring));
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(xhci_stream_context_array);
+
+void xhci_debugfs_create_stream_files(struct xhci_hcd *xhci,
+				      struct xhci_virt_device *dev,
+				      int ep_index)
+{
+	struct xhci_slot_priv	*spriv = dev->debugfs_private;
+	struct xhci_ep_priv	*epriv;
+
+	if (!spriv || !spriv->eps[ep_index] ||
+	    !dev->eps[ep_index].stream_info)
+		return;
+
+	epriv = spriv->eps[ep_index];
+	epriv->stream_info = dev->eps[ep_index].stream_info;
+
+	/* Show trb ring of stream ID 1 by default */
+	epriv->stream_id = 1;
+	epriv->show_ring = epriv->stream_info->stream_rings[1];
+	debugfs_create_file("stream_id", 0644,
+			    epriv->root, epriv,
+			    &stream_id_fops);
+	debugfs_create_file("stream_context_array", 0444,
+			    epriv->root, epriv,
+			    &xhci_stream_context_array_fops);
 }
 
 void xhci_debugfs_create_slot(struct xhci_hcd *xhci, int slot_id)

drivers/usb/host/xhci-debugfs.h

···
 struct xhci_ep_priv {
 	char			name[DEBUGFS_NAMELEN];
 	struct dentry		*root;
+	struct xhci_stream_info *stream_info;
+	struct xhci_ring	*show_ring;
+	unsigned int		stream_id;
 };
 
 struct xhci_slot_priv {
···
 void xhci_debugfs_remove_endpoint(struct xhci_hcd *xhci,
 				  struct xhci_virt_device *virt_dev,
 				  int ep_index);
+void xhci_debugfs_create_stream_files(struct xhci_hcd *xhci,
+				      struct xhci_virt_device *virt_dev,
+				      int ep_index);
 #else
 static inline void xhci_debugfs_init(struct xhci_hcd *xhci) { }
 static inline void xhci_debugfs_exit(struct xhci_hcd *xhci) { }
···
 xhci_debugfs_remove_endpoint(struct xhci_hcd *xhci,
 			     struct xhci_virt_device *virt_dev,
 			     int ep_index) { }
+static inline void
+xhci_debugfs_create_stream_files(struct xhci_hcd *xhci,
+				 struct xhci_virt_device *virt_dev,
+				 int ep_index) { }
 #endif /* CONFIG_DEBUG_FS */
 
 #endif /* __LINUX_XHCI_DEBUGFS_H */

drivers/usb/host/xhci.c

···
 		xhci_dbg(xhci, "Slot %u ep ctx %u now has streams.\n",
 			 udev->slot_id, ep_index);
 		vdev->eps[ep_index].ep_state |= EP_HAS_STREAMS;
+		xhci_debugfs_create_stream_files(xhci, vdev, ep_index);
 	}
 	xhci_free_command(xhci, config_cmd);
 	spin_unlock_irqrestore(&xhci->lock, flags);